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Infrared Spectroscopy Evidence of Weak Interactions in Frustrated Lewis Pairs Formed by Tris(pentafluorophenyl)borane |
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| Authors: | Leandro Ramos Marques Prof Rômulo Augusto Ando |
| Institution: | 1. Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Butantã, 05508-000 São Paulo-SP, Brazil
Contribution: Conceptualization (equal), Data curation (lead), Formal analysis (equal), Methodology (equal), Writing - original draft (equal), Writing - review & editing (equal);2. Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Butantã, 05508-000 São Paulo-SP, Brazil |
| Abstract: | Frustrated Lewis pairs (FLPs) have been widely investigated as promising catalysts due to their metal-free feature and ability to activate small molecules. Since their discovery, many works have been investigating how these Lewis pairs (intermolecular pairs) are held together in an encounter complex. This prompted several studies based on theoretical investigations, but experimental ones are limited yet. In this communication we show evidence of weak intermolecular interactions between Lewis acids and Lewis bases, distinguishing the Lewis adduct from FLPs, by probing fluorine-carbon vibrational modes using infrared spectroscopy. The main evidence is based on the band shifts occurring in FLPs due to weak hydrogen bonds between the hydrogen atoms of the Lewis base and the fluorine atoms of Lewis acid. |
| Keywords: | density functional calculations frustrated Lewis pair non-covalent interactions vibrational spectroscopy weak interactions |